IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 Influence of successive oxygen saturations of a grape juice, supplemented or not with laccase, on its color and hydroxycinnamic acids concentration

Influence of successive oxygen saturations of a grape juice, supplemented or not with laccase, on its color and hydroxycinnamic acids concentration

Abstract

Aim: This work studies how successive O2 saturations affects the color and hydroxycinnamic
acids concentration in the absence and presence of laccase from B. cinerea with the aim of better understanding the browning processes.

Materials and methods: Grapes of Muscat of Alexandria were harvested and pressed with a vertical press to extract 60% of their juice. Aliquots of 30 mL of this must were placed in 60 mL flasks equipped with a pill (PreSens Precision Sensing GmbH) for measuring oxygen by luminescence (Nomasense TM O2 Trace Oxygen Analyzer). These flasks were added or not with SO2 (50 mg/L) and with 2 UA/mL of laccase from B. cinerea (Giménez et al., 2022). All operations were carried out with a continuous nitrogen stream to protect the grape juice from air oxygen. The grape juices were then saturated in O2. The flasks were kept at 20±2 °C and O2 was monitored (Diéval et al., 2011). Once O2 was completely consumed, this operation was repeated twice to reach a total of three O2 saturations. Absorbances at 420, 320 and 280 nm were determined in all the samples. Hydroxycinnamic acids and GRP were analyzed by RP-HPLC-DAD-ESI-MS (Lago-Vanzela et al., 2013).

Results and discussion: Samples without SO2 and laccase consumed O2 after the 2st saturation in around 1 hour with an initial O2 consumption rate (OCR) of 0.262±0.009 mg of O2/minute. Surprisingly, no significant differences were found in the OCR of the samples supplemented with laccase in the 1st saturation (0.266±0.075). However, the OCR decreased significantly for the 2nd and 3rd saturations in the case of the samples without laccase (0.128±0.003 and 0.101±0.011 respectively) whereas no significant decrease was observed when laccase was present (0.268±0.013 and 0.238±0.049 respectively). The supplementation with SO2 almost completely inhibited OCR in both cases, without and with laccase (0.006±0.002 and 0.011±0.003 respectively). The A420 nm (yellow color) increased after each saturation and this augmentation was significant higher in the samples supplemented with laccase. In contrast, the A320 nm (hydroxycinnamic acids) and A280 nm (total phenolic compounds) do the opposite. Finally, caftaric and cutaric acids and in a minor extent fertaric acid concentrations decreased after each saturation and this decrease was very similar in the samples supplemented or not with laccase. In contrast, the samples supplemented with SO2 hardly showed changes in the different absorbances or in the hydroxycinnamic acids.

Conclusions:

These results confirm that SO2 is very effective to prevent browning even in the presence of laccase. This data also indicate that the presence of laccase provokes higher browning even consuming the same O2 than without its presence, probably because can use more substrates than natural grape tyrosinase

References

Diéval, J.B., Vidal, S., & Aagaard, O. (2011). Measurement of the oxygen transmission rate of co-extruded wine bottle closures using a luminescence-based technique. Packaging Technology and Science, 24, 375–385.
Giménez, P., Anguela, S., Just-Borras, A., Pons-Mercadé, P., Vignault, A., Canals, J.M., Teissedre, P.L., Zamora, F. (2022) Development of a synthetic model to measure browning caused by laccase activity from Botrytis cinerea. LWT – Food Science and Technology 154 (2022) 112871. 
Lago-Vanzela, E.S., Rebello, L.P.G., Ramos, A.M., Stringheta, P.C., Da-Silva, R., García-Romero, E., Gómez-Alonso, S. and Hermosín-Gutiérrez, I. (2013) Chromatic characteristics and color-related phenolic composition of Brazilian young red wines made from the hybrid grape cultivar BRS Violeta (‘BRS Rúbea’ × ‘IAC 1398-21’). Food Research International 54, 33–43.

DOI:

Publication date: June 23, 2022

Issue: IVAS 2022

Type: Article

Authors

Zamora Fernando 1, Giménez Pol1, Just-Borras Arnau1, Solé-Clua Ignasi1, Pérez-Navarro José2, Gombau Jordi1, Gómez-Alonso Sergio2 and Canals Joan Miquel1

1Departament de Bioquímica i Biotecnologia, Facultat d’Enologia de Tarragona, Universitat Rovira i Virgili, C/Marcel.li Domingo s/n, 43007 Tarragona, Spain
2Universidad de Castilla-La Mancha, Instituto Regional de Investigación Científica Aplicada. Ciudad Real, Spain

Contact the author

Keywords

Grape Juice, Oxidation, Browning, Laccase, Hydroxycinnamic Acids

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

Biodiversity in the vineyard agroecosystem: exploring systemic approaches

Biodiversity conservation and restoration are essential for guarantee the provision of ecosystem services associated to vineyard agroecosystem such as climate regulation trough carbon sequestration and control of pests and diseases. Most of published research dealing with the complexity of the vineyard agroecosystems emphasizes the necessity of innovative approaches, including the integration of information at different temporal and spatial scales and development of systemic analysis based on modelling. A biodiversity survey was conducted in the Franciacorta wine-growing area (Lombardy, Italy), one of the most important Italian wine-growing regions for sparkling wine production, considering a portion of the territory of 112 ha. The area was divided into several Environmental Units (EUs), defined as a whole vineyard or portion of vineyard homogenous in terms of four agronomic characteristics: planting year, planting density, cultivar, and training system. In each EU a set of compartments was identified and characterised by specific variables. The compartments are meteorology, morphology (altitude, slope, aspect, row orientation, and solar irradiance), ecological infrastructures and management. The landscape surrounding EU was also characterised in terms of land-use in a buffer zone of 500 m. For each component a specific methodology was identified and applied. Different statistical approaches were used to evaluate the method to integrate the information related to different compartments within the EU and related to the buffer zone. These approaches were also preliminarily evaluated for their ability to describe the contribution of biodiversity and landscape components to ecosystem services. This methodological exploration provides useful indication for the development of a fully systemic approach to structural and functional biodiversity in vineyard agroecosystems, contributing to promote a multifunctional perspective for the all wine-growing sector.

Sustaining wine identity through intra-varietal diversification

With contemporary climate change, cultivated Vitis vinifera L. is at risk as climate is a critical component in defining ecologically fitted plant materiel. While winegrowers can draw on the rich diversity among grapevine varieties to limit expected impacts (Morales-Castilla et al., 2020), replacing a signature variety that has created a sense of local distinctiveness may lead to several challenges. In order to sustain wine identity in uncertain climate outcomes, the study of intra-varietal diversity is important to reflect the adaptive and evolutionary potential of current cultivated varieties. The aim of this ongoing study is to understand to what extent can intra-varietal diversity be a climate change adaptation solution. With a focus on early (Sauvignon blanc, Riesling, Grolleau, Pinot noir) to moderate late (Chenin, Petit Verdot, Cabernet franc) ripening varieties, data was collected for flowering and veraison for the various studied accessions (from conservatory plots) and clones. For these phenological growing stages, heat requirements were established using nearby weather stations (adapted from the GFV model, Parker et al., 2013) and model performances were verified. Climate change projections were then integrated to predict the future behaviour of the intra-varietal diversity. Study findings highlight the strong phenotypic diversity of studied varieties and the importance of diversification to enhance climate change resilience. While model performances may require improvements, this study is the first step towards quantifying heat requirements of different clones and how they can provide adaptation solutions for winegrowers to sustain local wine identity in a global changing climate. As genetic diversity is an ongoing process through point mutations and epigenetic adaptations, perspective work is to explore clonal data from a wide variety of geographic locations.

Amino nitrogen content in grapes: the impact of crop limitation

As an essential element for grapevine development and yield, nitrogen is also involved in the winemaking process and largely affects wine composition. Grape must amino nitrogen deficiency affects the alcoholic fermentation kinetics and alters the development of wine aroma precursors. It is therefore essential to control and optimize nitrogen use efficiency by the plant to guarantee suitable grape nitrogen composition at harvest. Understanding the impact of environmental conditions and cultural practices on the plant nitrogen metabolism would allow us to better orientate our technical choices with the objective of quality and sustainability (less inputs, higher efficiency). This trial focuses on the impact of crop limitation – that is a common practice in European viticulture – on nitrogen distribution in the plant and particularly on grape nitrogen composition. A wide gradient of crop load was set up in a homogeneous plot of Chasselas (Vitis vinifera) in the experimental vineyard of Agroscope, Switzerland. Dry weight and nitrogen dynamics were monitored in the roots, trunk, canopy and grapes, during two consecutive years, using a 15N-labeling method. Grape amino nitrogen content was assessed in both years, at veraison and at harvest. The close relationship between fruits and roots in the maintenance of plant nitrogen balance was highlighted. Interestingly, grape nitrogen concentration remained unchanged regardless of crop load to the detriment of the growth and nitrogen content of the roots. Meanwhile, the size and the nitrogen concentration of the canopy were not affected. Leaf gas exchange rates were reduced in response to lower yield conditions, reducing carbon and nitrogen assimilation and increasing intrinsic water use efficiency. The must amino nitrogen profiles could be discriminated as a function of crop load. These findings demonstrate the impact of plant balance on grape nitrogen composition and contribute to the improvement of predictive models and sustainable cultural practices in perennial crops.

Spatial determination of areas in the Western Balkans region favorable for organic production

In problematic conditions for production of grapes and wine caused by the COVID-19 pandemic and the resulting occurrence of wine surpluses, producers are increasingly turning to the innovative viticulture and winemaking of products that are more appealing to the market and the consumers. On the other hand, consumption of the food safety or organic products, and therefore of organic grapes and wine, is increasingly common in the world, in particular in Europe. The Regional Rural Development Standing Working Group (SWG RRD), as a regional intergovernmental organization gathers actors in the viticulture and winemaking sector from states and territories of the Western Balkans (South-East Europe) in the Expert Working Group for Wine, with the aim of improving viticulture and winemaking in this region through joint activities. In accordance with the aforementioned, the SWG RRD is working on advancing organic production of grapes and wine, and on recognition of specificities of the terroir of wine-growing areas in Western Balkans. In addition, as part of the project “Facilitation of Exchange and Advice on Wine Regulations in Western Balkan Countries” helmed by the German Federal Ministry of Food and Agriculture, in addition to harmonization of relevant legislation with EU regulations, efforts are being invested towards recognition of organic wines. Within activities and project implemented by this organization, expert analyses and scientific research of the terroir of Western Balkans were carried out, and some of the results are presented in this paper.

Towards a regional mapping of vine water status based on crowdsourcing observations

Monitoring vine water status is a major challenge for vineyard management because it influences both yield and harvest quality. It is also a challenge at the territorial scale for identifying periods of high water restriction or zones regularly impacted by water stress. This information is of major importance for defining collective strategies, anticipating harvest logistic or applying for irrigation authorisation. At this spatial scale, existing tools and methods for monitoring vine water status are few and often require strong assumptions (e.g. water balance model). This paper proposes to consider a collaborative collection of observations by winegrowers and wine industry stakeholders (crowdsourcing) as an interesting alternative. Indeed, it allows the collection of a large number of field observations while pooling the collection effort. However, the feasibility of such a project and its interest in monitoring vine water status at regional scale has never been tested.

The objective of this article is to explore the possibility of making a regional map of vine water status based on crowdsourcing observations. It is based on the study of the free mobile application ApeX-Vigne, which allows the collection of observations about vine shoot growth. This information is easy to collect and can be considered, under certain conditions, as a proxy for vine water status. This article presents the first results obtained from the nearly 18,000 observations collected by winegrowers and wine industry stakeholders during 2019, 2020 and 2021 seasons. It presents the vine shoot growth maps obtained at regional scale and their evolution over the three vintages studied. It also proposes an analysis of the factors that favoured the number of observations collected and those that favoured their quality. These results open up new perspectives for monitoring vine water status at a regional scale but above they provide references for other crowdsourcing projects in viticulture.